Herbicidal imidazolin-2-yl pyridine and quinolinecarboxylic acids, esters and salts of formula I below, methods for their preparation and use are described in U.S. Pat. Nos. 4,638,068, issued Jan. 20, 1987, and 4,608,079, issued Aug. 26, 1986. ##STR1## wherein X is H, halogen, methyl or hydroxyl;
Y and Z are each hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, hydroxyloweralkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.4 alkylthio, phenoxy, C.sub.1 -C.sub.4 haloalkyl, nitro, cyano, C.sub.1 -C.sub.4 alkylamino, diloweralkylamino or C.sub.1 -C.sub.4 alkylsulfonyl group, or phenyl optionally substituted with one C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen, difluoromethoxy, trifluoromethoxy, 1,1,2,2-tetrafluoroethoxy, C.sub.3 -C.sub.8 straight or branched alkenyloxy optionally substituted with one to three halogens, or C.sub.3 -C.sub.8 straight or branched alkynyloxy optionally substituted with one to three halogens; PA1 R.sub.1 is C.sub.1 -C.sub.4 alkyl; PA1 R.sub.2 is C.sub.1 -C.sub.4 alkyl or C.sub.3 -C.sub.6 cycloalkyl; and when R.sub.1 and R.sub.2 are taken together with the carbon to which they are attached they may represent C.sub.3 -C.sub.6 cycloalkyl optionally substituted with methyl; PA1 R.sub.3 is hydrogen or COOR.sub.3 represents a salt or ester of the acid. PA1 Y and Z are each hydrogen, halogen C.sub.1 -C.sub.6 alkyl, hydroxyloweralkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.4 alkylthio, phenoxy, C.sub.1 -C.sub.4 haloalkyl, nitro, cyano, C.sub.1 -C.sub.4 alkylamino, diloweralkylamino or C.sub.1 -C.sub.4 alkylsulfonyl group, or phenyl optionally substituted with one C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen, difluoromethoxy, trifluoromethoxy, 1,1,2,2-tetrafluoroethoxy, C.sub.3 -C.sub.8 straight or branched alkenyloxy optionally substituted with one to three halogens, or C.sub.3 -C.sub.8 straight or branched alkynyloxy optionally substituted with one to three halogens; and when taken together, Y and Z may form a ring which may optionally be substituted, in which YZ are represented by --(CH.sub.2).sub.n --, where n is an integer of 3 or 4, or --(CH).sub.4 --; PA1 R.sub.1 is C.sub.1 -C.sub.4 alkyl; PA1 R.sub.2 is C.sub.1 -C.sub.4 alkyl or C.sub.3 -C.sub.6 cycloalkyl; and when R.sub.1 and R.sub.2 are taken together with the carbon to which they are attached they may represent C.sub.3 -C.sub.6 cycloalkyl optionally substituted with methyl; PA1 R.sub.3 is H or COOR.sub.3 represents an ester of the acid wherein R.sub.3 comprises hydrogen or loweralkyl optionally substituted by phenyl. PA1 R.sub.4 and R.sub.5 are each C.sub.1 -C.sub.4 alkyl or phenyl or when taken together, may form a C.sub.5 or C.sub.6 cycloalkyl; PA1 R.sub.1 is C.sub.1 1.varies.C.sub.4 alkyl; PA1 R.sub.2 is C.sub.1 -C.sub.4 alkyl; PA1 R.sub.3 is hydrogen, loweralkyl optionally substituted with phenyl; PA1 R.sub.4 is C.sub.1 -C.sub.4 alkyl; PA1 R.sub.5 is C.sub.1 -C.sub.4 alkyl or phenyl; PA1 X is H; PA1 Y is hydrogen or C.sub.1 -C.sub.4 loweralkyl; PA1 Z is hydrogen; PA1 R.sub.1 is methyl; and PA1 R.sub.2 is isopropyl.
and when taken together, Y and Z may form a ring which may optionally be substituted, in which YZ are represented by --(CH.sub.2).sub.n --, where n is an integer of 3 or 4, or (CH).sub.4 ;